CHANDRA ELECTRONIC ANNOUNCEMENT NUMBER 64

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Contents:

1. Science for Chandra's Second Decade

2. Probing higher resolution: an asymmetry in the Chandra PSF

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Item 1.  Science for Chandra's Second Decade
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The Chandra X-ray Center is pleased to announce an upcoming
opportunity, as part of the Cycle 13 Call for Proposals,to propose for
Chandra "X-ray Visionary Projects (XVPs)". XVPs encourage proposals for
up to 6-7 Msec of observing time that will allow the community to
harness Chandra's powerful capabilities to address major scientific
questions. 
 
An XVP proposal should describe a major, coherent science program to
address key, high-impact, scientific question(s) in current
astrophysics and may be multi-cycle in nature up to 3 years when
required to achieve the science goals. We envision that XVPs will
result in data sets of lasting value to the astronomical
community. There will be no proprietary time available for data
obtained as part of an XVP. We encourage proposers to describe the
legacy value of the data and any data products and/or software they
expect to release to the community as part of their project.  
 
We expect 6-7 Msecs of observing time to be dedicated to XVP proposals
in Cycle 13, allowing approval of one or more proposals requiring
between 1 and 6-7 Msecs of Chandra observing time. Time in future
cycles will be available, but limited to projects whose science
requires constrained observations spanning 2-3 years. Very Large
Projects will not be solicited in Cycle 13 since projects of this size
(> 1Msec) will fall within the new XVP category.  
 
The large time allocation for XVPs in Cycle 13 does not impact
observing time available for GO or Large Programs. This is due to a
number of factors, dominated by increased observing efficiency due to
the lower fraction of time spent within the radiation belts during the
next 2-3 cycles as Chandra's orbit evolves. We envision 1 or more
future solicitations for XVPs in upcoming, not necessarily contiguous,
cycles depending on assessment of potential science impact and
available observing time, and in consultation with Chandra Project
Science at MSFC and the Chandra Users' Committee. 
 
XVP Proposals should be submitted in response to the Cycle 13 Call for
Proposals to be released on 15 Dec 2010, with proposals due on 15
March 2011. They will be reviewed at the regular peer review in June
2011. Proposers will be asked to submit a Notice of Intent to propose,
including a likely title and list of investigators, in late
January. Full details will be available in the Cycle 13 Call for
Proposals.  
 

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Item 2.  Probing higher resolution: an asymmetry in the Chandra PSF
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A new Data Caveat

As part of efforts to push the spatial resolution of Chandra to the
sub-ACIS-pixel regime, we have identified a feature in the Chandra/HRC
point spread function within the central arcsecond which may affect
high fidelity deconvolutions. There is evidence that the feature is
also present in Chandra/ACIS data. The problem does not affect images
on scales larger than one arcsecond. 

Further details, including images of the artifact, are available at
http://cxc.harvard.edu/ciao/caveats/psf_artifact.html 

References:
    * Chandra's Ultimate Angular Resolution: Studies of the HRC-I
Point Spread Function
(http://hea-www.harvard.edu/~juda/memos/HEAD2010/HEAD2010_poster.html)
by Michael Juda & Margarita Karovska 

    * Analysis of Chandra PSF feature using ACIS data
(http://cxc.harvard.edu/cal/Hrc/PSF/acis_psf_2010oct.html) by Vinay
Kashyap 

The make_psf_asymmetry_region tool
(http://cxc.harvard.edu/ciao/ahelp/make_psf_asymmetry_region.html)
released as part of the CIAO contributed software
(http://cxc.harvard.edu/ciao/download/scripts/) creates a region file
indicating the location of the PSF asymmetry found in HRC and ACIS
data for a source at specific coordinates. 


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